• Journal of Korean Tunnelling and Underground Space Association
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• v.10 no.1
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• pp.1-15
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• 2008

Recently, because of the various factors by uncertainty of underground, the risks in tunnelling have been occurred increasingly. Therefore, it is very important to estimate and control the risks considering geotechnical conditions for tunnel stability and environmental problems by tunnel construction. In this study, the risk analysis for tunnel stability was carried out by classifying the risk factors such as ground support capacity, ground settlement, the inflow of groundwater into the tunnel and the damage by the earthquake. Also, the risk assessment for the environmental problems was performed by calculating the vibration and noise by blasting and the drawdown of the groundwater level caused by tunnel construction. Each risk factor was evaluated quantitatively based on the probabilistic and statistic technique, then it was analyzed the distribution characteristic along overall tunnel site. Finally, it was evaluated that how much each risk factor influences on the construction cost with a period for tunnel construction, so it is possible to perform reasonable tunnel design which was capable of minimizing the risks in the tunnel construction.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.3
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• pp.529-534
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• 2016

The paper suggests risk management methodology for alleviating casuality accidents at urban railway stations. Risk management deals with countermeasures for reducing accident probability or consequences to reach at the certain level of risk. First of all, Economic evaluations using cost and benefit for all the alternatives are performed. The alternatives exceeding B/C ratio greater than 1, each alternative is applied in the order of higher B/C ratio. this process is repeated when the level of risk is reduced as low as reasonably practical (ALARP). In order to determine the level of ALARP, Level of Service (LOS) for casuality risk at urban railway stations is proposed. The ALARP level is set to the LOS "C". Finally, a case study is applied to the Jongno 3-ga station, which is a highest risky station among all the stations operated by Seoul Metro and Seoul Metropolitan Rapid Transit Cooperation (SMRT).

• Journal of Digital Convergence
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• v.11 no.10
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• pp.71-77
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• 2013

Broadcaster and production studio inevitably take the risk in Korea because the outsourced drama is contracted before produced. However, it is important for both parties to share risk and reward. This study seeks to assess the fairness of the copyright contract between broadcaster and production studio by examining whether they both have the balanced risk and reward structure. For the study, revenue and cost elements with their amounts are identified, which come from TV commercials, oversea sales, the secondary windows, sponsorship, and product placement. Next, the revenue and COGS (Cost of goods sold) of broadcaster and studio are estimated for both cases of when drama becomes successful or not. The analysis reveals that the current copyright agreement allows broadcaster hold low risk but high reward whilst production studio takes high risk low reward. However, the result doesn't imply that government intervention is justified because demand and supply determine the negotiation power in a free economy.

• Industrial Engineering and Management Systems
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• v.11 no.1
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• pp.11-17
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• 2012

Along with the recent trend toward increasing variety and shorter life of products in the market, evaluation of risk for economic investment alternatives is of practical importance in manufacturing companies. This paper assumes that each alternative is composed of demand volume and unit sales price as income factors, and unit variable cost and fixed cost as expense factors. The paper assumes that these four factors move worse from the originally expected values, toward the direction of decreasing profit. Values of these four factors are also assumed to fluctuate from year to year over the entire multi-period. By applying the analysis of the breakeven points to each of the four factors, safer area against these changes is represented on the two dimensional domain called normalized total-cost unit-cost domain. A practical numerical example is analyzed to verify the validity of the proposed method.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2002.10a
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• pp.409-412
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• 2002

In this presentation, the methods that is appropriate to remediate the farmland contaminated by petroleum hydrocarbon was considered using the case histories of the abroad. As a result of a consideration, most remediation procedures were based risk assessment and management, risk-based procedure. It is also useful to use natural attenuation mechanism to remediate petroleum-contaminated sites. However, more research efforts are demanded for developing a cost-effective and efficient technologies.

• Journal of Distribution Science
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• v.20 no.12
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• pp.81-87
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• 2022

Purpose: This study aims to explore the relationship between stock liquidity and skewness risk-tail risk (stock price crash risk) in an emerging market, in which problems on liquidity are more severe than in developed markets. Research design, data, and methodology: Based on the Thai market stock exchange over the period of 2000 to 2019, our sample include 13,462 firm-period observations. We employ a panel regression models regarding to five liquidity measures. These five liquidity measures cover three dimensions of liquidity namely the volume-based, price-based, and transaction cost-based measures for the liquidity-tail risk relationship. Results: We find a positively significant relationship between stock liquidity and tail risk in all cases. The finding here shows that the higher the stock liquidity, the larger the tail risk is. Conclusion: As the prior studies show inconclusive effect of stock liquidity on stock price crash risk, we demonstrate that mixed results found in prior studies are probably driven from the type of liquidity measure. The stock liquidity-tail risk association is present in the Stock Exchange of Thailand. The results remain the same regardless of the definition of tail risk and liquidity factors. An endogeneity issue is addressed by employing the two-stage least squares regression.

• Computers and Concrete
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• v.25 no.2
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• pp.167-179
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• 2020

Optimal design of structures against earthquake loads is often limited to reduce initial construction costs, while the cost induced to structures during their useful life may be several times greater than the initial costs. Therefore, it is necessary to consider the indirect costs due to earthquakes in the design process. In this research, an integrated methodology for calculating life cycle cost (LCC) of moment-resisting concrete frames is presented. Increasing seismic safety of structures and reducing human casualties can play an important role in determining the optimal design. Costs incurred for structures are added to the costs of construction, including the costs of reconstruction, financial losses due to the time spent on reconstruction, interruption in building functionality, the value of people's life or disability, and content loss are a major part of the future costs. In this research, fifty years of useful life of structures from the beginning of the construction is considered as the life cycle. These costs should be considered as factors of calculating indirect costs of a structure. The results of this work represent the life cycle cost of a 4 story, 7 story, and 10 story moment-resisting concrete frame by details. This methodology is developed based on the economic conditions of Iran in 2016 and for the case of Tehran city.

• Journal of the Korea Safety Management & Science
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• v.20 no.3
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• pp.27-36
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• 2018

The steel pipe manufacturing industry deals with facilities and materials. Especially thermal facilities are close to vapor cloud explosion (VCE) and may cause secondary damage to facilities because they deal with corrosive substances such as hydrofluoric acid, sulfuric acid and acid, fire, explosion, leakage etc. It is in danger. In this study, hazard identification method was conducted using HAZOP techniques and quantitative risk analysis was conducted using e-CA, a program that supports accident impact analysis. Equipment in the influence range of ERPG - 3 was determined to be a facility requiring replacement. It was decided that neutralization is necessary using slaked lime. Based on the cost of loss, We presented the proper replacement which is the timing of the dangerous facility. As a result, It was ideal to replace the facilities with 20 years of heat treatment facilities, one year of hydrofluoric acid storage tank, 20 years of sulfuric acid storage tank, and 5 years of hydrochloric acid storage tank.

• International conference on construction engineering and project management
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• 2022.06a
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• pp.823-830
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• 2022

The risk of project execution increases due to the enlargement and complexity of Engineering, Procurement, and Construction (EPC) plant projects. In the fourth industrial revolution era, there is an increasing need to utilize a large amount of data generated during project execution. The design is a key element for the success of the EPC plant project. Although the design cost is about 5% of the total EPC project cost, it is a critical process that affects the entire subsequent process, such as construction, installation, and operation & maintenance (O&M). This study aims to develop a system using machine-learning (ML) techniques to predict risks and support decision-making based on big data generated in an EPC project's design and construction stages. As a result, three main modules were developed: (M1) the design cost estimation module, (M2) the design error check module, and (M3) the change order forecasting module. M1 estimated design cost based on project data such as contract amount, construction period, total design cost, and man-hour (M/H). M2 and M3 are applications for predicting the severity of schedule delay and cost over-run due to design errors and change orders through unstructured text data extracted from engineering documents. A validation test was performed through a case study to verify the model applied to each module. It is expected to improve the risk response capability of EPC contractors in the design and construction stage through this study.

• Journal of Korean Society of Transportation
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• v.23 no.3 s.81
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• pp.95-108
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• 2005

The purpose of this study is to develop the ITS evaluation model using the Probabilistic Risk Analysis (PRA) methodology and to demonstrate the goodness-of-fit of the large ITS projects through the comparative analysis between DEA and PRA model. The results of this study are summarized below. First, the evaluation mode] using PRA with Monte-Carlo Simulation(MCS) and Latin-Hypercube Sampling(LHS) is developed and applied to one of ITS projects initiated by local government. The risk factors are categorized with cost, benefit and social-economic factors. Then, PDF(Probability Density Function) parameters of these factors are estimated. The log-normal distribution, beta distribution and triangular distribution are well fitted with the market and delivered price. The triangular and uniform distributions are valid in benefit data from the simulation analysis based on the several deployment scenarios. Second, the decision making rules for the risk analysis of projects for cost and economic feasibility study are suggested. The developed PRA model is applied for the Daejeon metropolitan ITS model deployment project to validate the model. The results of cost analysis shows that Deterministic Project Cost(DPC), Deterministic Total Project Cost(DTPC) is the biased percentile values of CDF produced by PRA model and this project need Contingency Budget(CB) because these values are turned out to be less than Target Value(TV;85% value), Also, this project has high risk of DTPC and DPC because the coefficient of variation(C.V) of DTPC and DPC are 4 and 15 which are less than that of DTPC(19-28) and DPC(22-107) in construction and transportation projects. The results of economic analysis shows that total system and subsystem of this project is in type II, which means the project is economically feasible with high risk. Third, the goodness-of-fit of PRA model is verified by comparing the differences of the results between PRA and DEA model. The difference of evaluation indices is up to 68% in maximum. Because of this, the deployment priority of ITS subsystems are changed in each mode1. In results. ITS evaluation model using PRA considering the project risk with the probability distribution is superior to DEA. It makes proper decision making and the risk factors estimated by PRA model can be controlled by risk management program suggested in this paper. Further research not only to build the database of deployment data but also to develop the methodologies estimating the ITS effects with PRA model is needed to broaden the usage of PRA model for the evaluation of ITS projects.